Update: Two verdicts of guilty, one not guilty: that was the conclusion of the mock ecocide trial (details below) held at the UK's supreme court on 30 September. Real lawyers, judges and a public jury found the CEOs of fictional fossil fuel companies guilty of "extensive destruction, damage to or loss of ecosystem(s) to such an extent that the peaceful enjoyment by the inhabitants of that territory, and of other territories, has been severely diminished", as a result of their company's extraction of oil from tar sands in Canada. The jury found one of the CEOs not guilt on the count of damage caused by an oil spill in the Gulf of Mexico.

Polly Higgins, the driving force behind the trial and who is working to have ecocide join genocide and three other crimes against peace in the UN, said: "For me the trial was a moment of truth. No longer is it acceptable to pursue profit without consequence. Corporate Ecocide is a global crime that is far greater and far more prevalent that most people realise. Those few people who dare to speak up about Corporate Ecocide in Wall Street have been arrested for speaking out about a greater crime, a far greater breach of the peace than their own shouting and campaigning. Surely it is now the time to prosecute the true destroyers of our world."

She added: "I'm not keen to see lots of [people] in the dock. What I want to see is people making responsible decisions. For example, a crime of ecocide could force governments to change the incentive structures for businesses by redirecting subsidises for fossil fuels towards clean energy sources. In this way the dirty energy companies that are wrecking the environment today could be transformed into the clean energy companies of tomorrow."Original story (29/09/11): It's a grim list: genocide, crimes against humanity, crimes of aggression (such as unprovoked invasions) and war crimes. All are recognised by the UN as crimes against peace and prosecuted through the international criminal court.

But should the bosses of polluting companies and the leaders of environmentally-unfriendly states join those responsible for mass murder in the dock. They could if a fifth crime against peace - ecocide - joined that list of human evils? The United Nations is now considering the proposal and the first test of how a prosecution for ecocide would work takes place on Friday, with fossil fuel bosses in the dock at the UK supreme court in London. It is a mock trial of course, but with real top-flight lawyers and judges and a jury made up of members of the public. The corporate CEOs will be played by actors briefed by their legal teams.

Ecocide: The extensive damage, destruction to or loss of ecosystems of a given territory, whether by human agency or by other causes, to such an extent that peaceful enjoyment by the inhabitants of that territory has been severely diminished.

Crimes being considered for prosecution in Friday's trial include the extraction of oil from Canada's tar sands, a major oil spill in the Gulf of Mexico, fracking for shale gas in Nigeria and bauxite mining of Niyamgiri mountain, India. The real world parallels are not accidental, I'm sure.

An international law against ecocide, enforceable in the UK, will be assumed for the purposes of the mock trial. But there is no script and the jury's verdict is theirs alone to decide. "It is nerve-racking, it is not a done deal," says Higgins.

She argues the link between ecocide and genocide is that damage and destruction to the environment depletes the Earth's resources, which leads to conflict. Only by making ecocide a crime for which individuals can be jailed, will we change the norm which allows profit to be put before the planet, she told me.

Higgins says a key inspiration is William Wilberforce, whose campaigning led to the abolition of slavery in the UK. He changed to norm of how black people were treated, she says, and ecocide law would change the way the planet is treated. "We have go to the point when the ethical imperative trumps the economic imperative," she says. At the moment in many countries, she points out, the first responsibility of CEOs is a financial one to their shareholders. If environmental destruction is not illegal but can boost profit, it will happen, she says.

But she is not anti-corporate or anti-profit, she says: "I started as a corporate lawyer. Now I want to make the problem part of the solution." She says companies should be making profits from solving the problems of global warming, habitat destruction and the extinctions of animals and plants. The companies that traded in slaves did not go out of business after slavery was abolished, she claims.

I asked her about the problem of proving causation between the acts of companies and environmental damage, which has doomed previous attempted prosecutions in the US.

"Genocide is a crime of intent, but ecocide is not," she says. An ecocide law would create a pre-emptive responsibility to prevent ecological damage, she explains, in the same way that "superior responsibility" or "strict liablility" enables people to be prosecuted whether or not they intended to cause damage. "I am really not wanting to see lots of CEOs locked up," she says, but wants them deterred from ecocide in the first place.

I also asked her about the phrase in her ecocide definition that says "whether by human agency or by other causes". If there is a natural disaster, who can be prosecuted? The "other causes" term is there, she says, to place an obligation on governments to intervene in disasters to minimise damage.

If this all seems utter fantasy to you, it is worth noting that Bolivia has already passed laws granting all nature equal rights to humans. Furthermore, ecocide could become an international crime by amendment of the ICC's Statute of Rome, which would need 86 nations to back it. Are there 86 states backing the ICC who feel climate change, the crisis in the oceans and other environmental problems are trashing their "peaceful enjoyment" of the Earth's bounty? I wouldn't be surprised if there were.

Update (11:22 Friday): The two crimes chosen for the ecocide mock trial are the extraction of oil from Canada's tar sands, a major oil spill in the Gulf of Mexico. I'll update the post again when the verdict comes.

Note: The trial, organised by the Hamilton Group, begins at 0900 BST on Friday 30 September and will be broadcast live by Sky News's Supreme Court web channel. Members of the public can attend. I'll post updates on this page. Michael Mansfield QC leads the prosecution against Nigel Lickley QC for the defence. Michael Norman will sit as the judge and the jury are members of the public recruited through Facebook and other social media and vetted for conflicts of interest.